I don't have problems with string corrosion, but I noticed that when I loaned my acoustic (using 80/20 bronze strings) to a friend, the strings were corroded due to the acids/chemicals in his hands. You might try using strings with a different metal composition - Fender and Ernie Ball both make Stainless Steel strings. The Elixer strings are also supposed to be good and last a long time due to the polymer coating, but they are pretty expensive.